1. Field of the Invention
The present invention relates generally to imaging devices and, more specifically, to imaging devices to which an Automatic Document Feeder (“ADF”) may be optionally attached.
2. State of the Art
An imaging device, such as a scanner, copier, facsimile machine, or the like, may include an ADF to automatically feed target media to the imaging device for processing, namely, scanning, copying, printing, faxing, or other printed material analysis. For example, an ADF attached to a scanner may feed each sheet of a document, one sheet at a time, to a flatbed imaging surface of the scanner and remove the sheet from the flatbed imaging surface once the imaging process of the scanner is complete. Thus, an ADF greatly reduces the amount of time required to process a target media with an imaging device.
An imaging device may include an ADF as an optional accessory that may be installed either by the manufacturer or the user of the imaging device. The installation process may include configuring the imaging device for use with the particular ADF attached to it by performing an adjustment and calibration procedure. The adjustment and calibration procedure may produce parameters used by the imaging device to compensate for changes in imaging quality and physical misalignments of target media during the imaging process. When an ADF is installed at the factory of the manufacturer, the imaging device may be configured by programming the presence of the ADF into the nonvolatile random access memory (“RAM”) of the device's controller. Adjustment and calibration values for the particular ADF may also be programmed into the nonvolatile RAM as part of the installation.
When an optional ADF is installed onto an imaging device by a user, the imaging device's controller typically needs to detect the presence of the ADF before the controller will use the ADF to process a target media. Thus, a conventional user installation process may include manually selecting the ADF as the source of the target media or automatically detecting a signal when an ADF has been attached to the imaging device. An external communication cable connected between the ADF and imaging device during installation typically provides all electrical communication between the ADF and imaging device and may provide an ADF detection signal to the imaging device's controller.
However, in order to reduce the size and cost of the communication cable, the communication cable's connectors and mating connectors located on the ADF and imaging device, it is advantageous to limit the number of signals carried by the communication cable to the functional signals required for the normal operation of the ADF. Therefore, it is desirable to detect the presence of the ADF without adding an ADF detection signal to the communication cable.